1. Field of the Invention
The present invention relates to a film-winding device for camera, more particularly to a film-winding device with a film-press spring for pressing a photographic film on a take-up spool.
2. Description of the Prior Arts
A film cartridge of IX 240 type (it will be mentioned as a film cartridge in the following) has been widely on sale. The film cartridge consists of a photographic film and a plastic cartridge to contain the photographic film entirely. The cartridge consists of a cartridge spool that winds the photographic film and a housing that contains the cartridge spool in a rotatable manner.
A spool drive shaft is rotatably protruded in a cartridge chamber. When the film cartridge is loaded into the cartridge chamber, the spool drive shaft connects to the cartridge spool. When the cartridge spool is rotated by the spool drive shaft, the photographic film is advanced from the cartridge. A film passage path is formed between the cartridge chamber and the take-up chamber. The photographic film, passing trough the film passage path, is advanced from the cartridge chamber to the take-up chamber frame by frame. An exposure aperture is formed in the middle of the film passage for determining a exposure determining an exposure area of the photographic film.
In the take-up chamber, there are disposed a take-up spool for rolling a photographic film and a film-press spring for pressing the photographic film on the take-up spool. The film-press spring is fixed into the take-up chamber by a screw, caulking, and the forth. According to the camera disclosed in Japanese Patent Laid-open Publication No. 9-222648 (corresponding to U.S. Pat. No. 6,006,044), the film-press spring is pressed onto a groove in order to be fixed. The photographic film into the take-up chamber is pressed to the take-up spool by the film-press spring to advance along the surroundings of the take-up spool. The photographic film is advanced further, the leading end of the photographic film is inserted between a part of the photographic film, which is pressed by the press spring and the surroundings of the take-up spool. After that, owing to the frictional force by a slip prevention member formed around the take-up spool, the photographic film is wound around the take-up spool in a coil.
However, the method to fix the film-press spring by use of screws, caulking, and the like decreases work performance upon attachment and increases the step of work because a space of the take-up chamber is narrow. As a result, the manufacturing cost goes up. Likewise, the method to press the film-press spring into a groove is good in work performance upon attachment. But it also has disadvantage that it is easily come off from the groove because the film-press spring is urged to the extracting direction at all times upon rolling the film.
In view of the foregoing, a primary object of the present invention is to provide a film-winding device whose work performance is good upon attachment of a film-press spring.
Another object of the present invention is to provide a film-winding device in which a film-press spring is fastened without fail.
And final object of the present invention is to provide a film-winding device that realizes reduction in costs by reducing the step of work.
In order to achieve the above and other objects, the film-winding device of the present invention is provided with a film-press spring disposed in a take-up chamber and a spring attachment hollow for holding the film-press spring. The film-press spring has a support section that is elastic and transformable in order to be inserted into the spring attachment hollow. A fitting arm and a slip prevention claw are integrally formed in the support section. The fitting arm presses a wall surface of the spring attachment hollow so as to hold the film-press spring. The slip prevention claw is engaged with the wall surface of the attachment hollow to prevent the film-press spring from being slipped. The slip prevention claw is engaged to the side wall surface of the spring attachment hollow or the end wall surface that crosses with the side wall surface.
According to the film-winding device of the present invention, inserting the support section of the film-press spring into the spring attachment hollow leads to a decrease in work step and simplification of an attachment operation because the film-press spring is fixed to the take-up chamber. In addition to that, since the slip prevention claw is engaged with the wall surface of the spring attachment hollow as well as the fitting arm presses the wall surface of the spring attachment hollow, the film-press spring is surely fastened.